Continuity mistake: When Edwards is first discovered missing by Grace, the moon is in the background in the center of the screen. After all the time that goes by with Edwards in the casino, Charles looking for him, finds him and goes all the way back to where they were sleeping (figure at least an hour or more), the moon is still in the exact same position in center of screen from the exact same camera angle. In reality, the moon would have been more to the right or disappeared completely by now (depending on the timespan).
Continuity mistake: When Mary and Laura dive into the lake to rescue the puppies they have their shoes on. As they are swimming around looking for them they are barefoot. When the get out of the water their shoes are back on.
Laura: I wanted to clean the blackboards extra good today, to make up for being late.
Mary Ingalls Kendall: And talking in class?
Laura: I was not talking.
Mary Ingalls Kendall: You were, too.
Laura: Was not! Nellie was talking and I was answering.
Trivia: Peter Billingsley of "A Christmas Story" plays Gideon in this episode. This was his television debut at age 11.